Knit goods printing process



Jan. 19, 1960 E. v. DISCH 2,921,517

KNIT GOODS PRINTING PROCESS Filed July 7, 1955 u; INVENTQR. tn 1145 V-KNIT GOODS PRINTING PROCESS Ellis V. Disch, Norwich, Conu., assiguor toPlastic Film Corporation, Plainfield, Conn., a corporation of DelawareApplication July 7, 1955, Serial No. 520,487

1 Claim. (Cl. 101-426) This invention relates to the art of printingdesigns on readily stretchable fabrics, and especially to the printingof multi-color designs on knit goods and the like.

A principal object of the invention is to provide a printing machine ofthe multi-color rotary printing drum kind which is especially designedand adapted to print multi-color designs on stretchable fabrics such asknit goods, with maximum accuracy of color registration by preventingthe fabric from being stretched or otherwise dimensionally distortedduring the printing operations.

Another object is to provide a printing machine of the rotary printingdrum multi-color kind for printing on readily stretchable materials,such as knit goods, with permanent inks of the resinous base kind.

A further object is to provide a machine for insuring accuracy ofregistration of multi-color printings on readily stretchable materialssuch as knit goods and the like.

A feature of the invention relates tothe novel organization,arrangement, and relative location and interconnection of parts, whichcooperate to provide an improved multi-color printing machine forstretchable fabrics.

Other features and advantages not particularly enumerated will beapparent after a consideration of the following detailed descriptionsand the appended claim.

The drawing shows, by way of example, one preferred embodiment of arotary drum multi-color fabric printing machine, for printing andprocessing printed designs on knitted fabrics such as sheer nylons,rayons, cotton, or Wool fabrics, so as to produce a design which issubstantially free from fading or wash-out when the goods are subjectedto washing.

While the art of multi-color printing on relatively nonstretchablematerials, such as paper and the like, has reached a high degree ofdevelopment, the mechanisms used in that particular application have notalways been found practicable for printing in multi-color on stretchablematerials such as knit or woven fabrics. That is especially true wherethe fabrics are to be printed in multi-color in a continuous feedingoperation using engraved printing rolls, as distinguished fromreciprocating or linearly moving printing heads. In the latter kind ofmachine it is possible to hold the fabric stationary against a suitablefiat backing and then to move the printing head into contact with thegoods. Consequently, in that type of fabric printing, registration ofthe various colors can be readily achieved and the problem ofdimensional distortion of the fabric is not as critical as it is wherethe printing is to be done by engraved rollers which continuouslycontact with and press against the fabric. It has been found that whenusing conventional engraved rollers to print rnulti-color designs andfabrics, the problem of color registration is exceedingly difiicult tomeet. One reason for that is that the fabric, not being self-supportingand in many cases for example in the case of nylons, rayons, andsynthetic fibers where the fabric is extremely sleazy, unavoidablybecomes dimensionally distorted. Even when complicated anti-skewingequipment is used, the accuracy of the respective multinited StatesPatent "ice color registrations is not always obtained. I have foundthat in order to achieve completely uniform results in the multi-colorprinting of stretchable fabrics with resin base inks it is necessary tosubject the printed fabric to a preliminary drying operation to driveolf the liquid constituents of the printing ink without correspondinglyshrinking or distorting the fabric and then to subject the printeddesign to a final heating and cooling operation to cure and set the inkand stabilize the fabric. Furthermore, in order to prevent distortion inthe multi-color registrations, I have found it necessary to synchronizethe various web feeding elements at the various stages so that at nopoint is the fabric subjected to any substantial stretch or dimensionaldistortion.

Accordingly, in the drawing the numeral 1 represents a roll of thestretchable fabric to be rnulti-color printed, such as knitted goods orwoven goods as received from the mill. This mill roll is supported fordownward rolling movement by gravity on a pair of inclined ways orguides 2, and the weight of the roll holds it in contact with apositively driven unwind roll 3 covered with rubber or other similarmaterial. Preferably the ways 2 and the mill roll may be supported onany suitable tilt- I able frame-4 whose angular position canbe-adjustedfor example by a hand wheel 5. The fabric 6 from the roll 1engages the under periphery of the rubber covered roll 3, and thenpasses upwardly and around the nip-forming roll 7 which is mounted as anidler roll and is arranged to press the fabric against the printingdrum.8 around which the fabric passes for approximately percent of thedrum periphery. The idler roll 7 is preferably carried by the frame 4 sothat by adjustment of the hand Wheel 5 the pressure between the roll andfabric and against the drum 8 can be accurately controlled.

The printing drum 8 is driven by the printing rollers 10, 11, 12, and13, so as to impart auniform rotational speed to the drum 8. Drum 8drives the idler roll 7 by its frictional engagement with web 6.Therefore, the roll '7 effects no dimensional distorting influence onthe web. Furthermore, the inclined or pull roll 3 is also positivelydriven at a fixed speed ratio with respect to drum 8, as schematicallyrepresented by the dot-dash line and schematic gearing symbol. Thisratio is chosen so that the linear speed of movement of the web 6 isuniform throughout its length, and thus it is not subjected to anysubstantial tension in the direction of its length.

In order to prevent endwise slippage or skewing of the fabric 6, thesurface of drum 8 is lapped by a cotton cloth which has been treated sothat the knit fabric 6 is frictionally held on the drum 8 againstslippage and stretching.

Located around the printing drum 8 are a series of multi-color engravedprinting rolls of which four such rolls are shown, namely rolls 10-13.These engraved printing rolls are positively driven at a fixed speed sothat the printing pressure on the fabric does not subject it to anydrag, stretch, or other dimensional distortion. The engraved printingrolls are provided with respective ink pans or reservoirs 14-17, andwith respective'ink applicator rolls 18-21 and respective doctor blades22-25. Each of the pans 14-17 is filled with a respective coloredprinting ink preferably of a kind which has a resinous or plastic base.Such resin base inks are well known in the printing art. A typicalexample of such inks may consist of vinyl acetate-chloride copolymermixed with a suitable plasticizer such as dioctyl phthalate in asuitable solvent,

for example methyl ethyl ketone, and a suitable coloring pigment. I

I have found that in order to produce the best results when multi-colorprinting with such inks, it is necessary to subject the printed designto a preliminary controlled heat treatment. For that purpose the printedfabric, after leaving the drum 8, is substantially directly transferredto an endless conveyor belt 26 which extends around a series of rollers27-32. Rollers 27-32 are idler rollers, whereas roller 32 is abeltdriven roller and is driven in fixed speed ratio with respect to drum 8,as indicated schematically by the dot-dash line and gearing symbol inthe drawing, this ratio being chosen so that the linear movement of thefabric 6 on the conveyor 26 is the same throughout its length.

In order that no substantial unsupported span of the printed fabricexists, the roller 27 is located so that the initial end of the conveyorbelt is as close as possible to the drum 8, for example within a spaceof a few inches. I have found that this is necessary since thesleaz'iness and non-self-supporting properties of certain fabrics mightotherwise entail undesirable sagging and distortion thereof. It will beunderstood, of course, that a very slight slack is desirable in thefabric between the point where it leaves the drum 8 and the point whereit actually engages the conveyor belt 26.

The conveyor 26 is enclosed within a suitable oven 33 provided with aplenum chamber, whose inlet end is connected by a duct 34-to a source ofdry heated air which is blown in the direction of the arrow and exits atthe opposite end of the oven through an exhaust duct 35 which may beprovided with an exhaust fan or the like. Thus, the liquid vehicle inthe inked design on the fabric is subjected to a continuous stream ofwarm dry air which moves without agitation .or recirculation through theplenum chamber of oven 33. It is important that the drying stream besubstantially smoothly continuous so as not to subject the printedfabric to any fluttering as it is passing through the oven. Furthermore,this drying stream is controlled so that the evaporation of the liquidvehicle of the printed design'is gradually evaporated so as to avoid anyshrinkage of the fabric. At this stage, after leaving the oven 33, theprinted ink design on the fabric is neither permanent nor washable. v

I have found that in order to achieve the desired degree of permanencyand washability of the printed ink design, it is necessary to subject itto an ink curing operation. This is effected by passing the printedfabric in a sinuous path between and around a series of curing rolls,fifteen of which are shown in the drawings and designated 36-50. Theserolls are shown mounted in a substantially vertical array in 'a suitableframe 51, and they are positively driven in fixed speed ratio withrespect to drum 8 so that they do not disturb the desired uniformity oflinear movement of the printed fabric and'thus protect it against anymechanical stretching.

The roll 50 is driven from motor 9 through suitable gearingschematically illustrated, and the successive rolls 36-50 may be gearedtogether also as schematically illustrated. All of the rolls may be ofhollow construction, and the first twelve rolls, namely rolls 36-47 aresteam heated, while the remaining three rolls, namely 48-50,'are watercooled. It will be understood, of course, that the invention is notlimited'to any particular manner of heating the rolls 36-47, providedthey are maintained ata temperature-of approximately 300 degrees F.After the printed fabric has been subjected to the heating and coolingstages to effect curing and permanentizing of the printed design, thefabric is transferred to a double drum rewind comprising for example thepositively driven rewind rolls '52, 53, and the receiving roll 54 'or57. Roll '54 may be supported on suitable inclined ways 55 so as to beheld by gravity in contact with the rewind roll 53. Preferably, a.rubber guide roll 56 is provided between the cooling roll 50 and therewind roll 52, it being understood that the rewind rolls 52 and 53 aredriven in synchronism with the remaining rolls so 'as not to disturb theuniform linear motion of the fabric.

One of the outstanding advantages of the machine, in addition to thosealready described, is the fact that if the fabric 6 has been pre-shrunkby any well known shrinking process prior to feeding it into theprinting machine above described, the fabric can be printed without thenecessity of further processing or pre-shrinking prior to conversion toconsumer goods. Furthermore, by the use of the machine and process asdescribed, it is possible to print piled knit fabrics with little, ifany, stretch or other dimensional distortion. It will be understood, ofcourse, that the invention is not limited to the application of openworkdesigns since the fabric can be printed all over its surface with asingle solid color. In other words, the machine, while it finds itsprimary utility in multicolor printing of fabrics, can also be used toapply a single over-all 'color coat to the fabric through the medium ofan etched printing roll. By the expression curing and setting of thewell known resin base ink, as used herein, is meant the heating of thepreviously dried ink to a temperature of approximately 300 degrees F.,which results in what is well known as the resin ink setting or beingpermanently attached to the fabric; as distinguished from thepreliminary heating which is done gradually merely to drive off theliquid constituents of the ink as hereinabove described.

Various changes and modifications may be made in the machine and processas disclosed without departing from the spirit and scope of theinvention.

What is claimed is:

The method of printing a stretchable fabric with a permanentized resinbase ink which comprises applying the ink to the fabric whilemaintaining the fabric in a continuous uniform motion, subjecting theprinted fabric to a preliminary drying heat to gradually drive off theliquid components of the ink and at a temperature such as to avoid anyshrinkage of the fabric, but leaving the printed design non-permanentand non-washable, then passing the printed fabric with its oppositefaces in engagement with a series of heating rolls at a temperature ofapproximately 300 degrees F. whereby the substantially immediatelyadjacent areas of the fabric on its opposite faces are simultaneouslyheated and with substantially negligible length of the fabric betweenadjacent heating rolls left unsupported, whereby substantially theentire length of the fabric on both faces is uniformly heated to saidtemperature of approximately 300 degrees F. to render the printed designpermanent and washable.

References Cited in the file of this patent UNITED STATES PATENTS1,315,377 McGiehan Sept. 9, 1919 1,541,806 Flick June 16, 1925 1,842,195Pinder Jan. 19, 1932 1,867,405 GLlfWlCk July 12, 1932 2,098,118Wheelwright Nov. 2, 1937 2,129,277 Jeuck Sept. 6, 1938 2,131,257 RisleySept. 27, 1938 2,254,072 Jenkins Aug. 26, 1941 2,276,181 Foster Mar. 10,1942 2,337,348 Prindle Dec. 21, 1943 2,358,112 Smith Sept. 12, 19442,434,013 Ross Jan. 6, 1948 2,656,327 Van 'Wirt Oct. 20, 1953

